Increase of Enterobacter in neonatal sepsis: a twenty-two-year study

Data on the incidence of Enterobacter infections in neonates over prolonged periods of time are scant. We determined the epidemiology of Enterobacter sepsis and/or meningitis and the trends of infection in a neonatal unit.

Retrospective review of sepsis and/or meningitis in inborn neonates admitted to Son Dureta University Hospital during a 22-year period. Molecular study by ribotyping of the Enterobacter strains isolated from 1995 to 1997.

There were 513 cases of culture-proved sepsis and/or meningitis in neonates. In late onset infections Klebsiella pneumoniae and Staphylococcus epidermidis were the most frequent isolates in the period 1977 through 1991. Enterobacter was the most common isolate in the period 1992 through 1998. During this latter period Candida infections also increased, and the resistance rate of Enterobacter to cefotaxime was higher (59.2%). Decrease in early onset infections and increase in late onsets (4.6/1,000 live births) were observed in the second period. From 1977 to 1998, 45 episodes of sepsis and/or meningitis by Enterobacter species were identified in 44 patients (8.7% of all neonatal bacteremias). Three patients with Enterobacter bacteremia died (6.6%, 0.03/1,000 live births). During 1995 through 1997 5 different clones causing sepsis were identified and 3 were predominant. In 1997 there was an outbreak of Enterobacter disease. After cleaning, cohort nursing and hygiene reinforcement, Enterobacter was not isolated in the next 2 years. No change in the antibiotic policy was made.

We observed a resurgence of Enterobacter infections in our neonatal intensive care unit. The sudden disappearance of this microorganism after reinforcement of hygienic measures, without withdrawing cefotaxime, confirms the importance of patient-to-patient transmission of this nosocomial infection. Further studies are needed to establish the role of antibiotics in the emergence of microorganisms in neonatal intensive care units.